Transmission



May 22, 1945- w. T. LNERMORE 2,375,545

TRANSMISSION 4Filed Dec. 24, 1957 5 Sheets-Sheet 1 e w m .w n

ATTORNEY.`

May 22, 1945. l w. T. LIVERMORE TRANSMISSION Filed Dec. 24, 1937Sheets-Sheet 2 E] INVENTOR.

M a 5 TL/'l/e/more ATTORNEY.

May 22, 1 945.- w. T. LIVERMORE 2,376,545

TRANSMI S S ION Filed Dec. 24, 1937 5 SheeS-Sheet 5 fai INVENTOR.

ATTORNEY.

5 Sheets-Sheet 4 INVENTOR. /4/////a/77 T/l/e/'mo/e ATTORNEY.

May 22, 1945. w. T. I NERMORE TRANSMISSION Filed Dec. 24, 1957 May 22,1945- w. T. LIVERMORE 2,376,545

TRANSMISSION Filed Dec. 24, 1957 5 Sheets-Sheet 5 y l INVENTOR, M//fam7." L /f/e/more BY gum Patented May 22, 1945 UNITED STATES PATENT OFFICETRANSMISSION William T. Livermore, Grosse Pointe, Mich. ApplicationDecember 24,1937, Serial No. 181,679

24 Claims.

This invention relates to transmissions for use with automotive vehiclesand is particularly disclosed herein as a type of transmission which isautomatically operated by a fluid pressure mechanism thereby eliminatingthe necessity for manual gear shifting.

Certain fundamental features of automatic transmissions have beendeveloped by myself and are disclosed in United States issued PatentsNos. 2,019,146 and 2,100,810 and applications Serial Nos. 603,823 and715,065. The present embodiment although it includes certain featuresdisclosed in my other applications, is a development which has been thedirect result of a considerable amount of additional research andexperimental work. The present transmission is designed withconsideration for size and arrangement thereby to provide a compact unitcomparable in size with standard manually operated units.

Several of my earlier designs of transmissions, of the type described inthe aforementioned patent applications, comprise a plurality ofconstantly meshed gear trains one for each of the gear ratios desired,there being an individual clutch to connect each individual gear trainfor operation. For automatic operation of this type of transmission afluid pressure mechanism Was used to actuate the clutches, thismechanism being under the control of a unit which was actuated by thecombined elect of members movable in proportion to vehicle speed andengine output.

The present invention, while employing many of the fundamental featureswhich were described and claimed in my previous applications, providesnovel and important improvements thereon in both the general gear andclutch arrangement and in the liuid pressure mechanism for automaticallyoperating the transmission. The gear and clutch unit in my improveddesign is considerably simplied both in number of parts and manner ofoperation, there being two separate clutches of such size andarrangement that they may be housed in the flywheel in substantially thesame space as the present day conventional clutch unit. These twoclutches are suiTcient to provide automatic operation for three forwardspeeds by the provision of an automatically operated shifting devicewhich changes the gear ratio of the gear train connected to one of theclutches While the other is in operation. 'I'his automatic gear shiftingmechanism preferably includes a socalled synchronizer unit which bringsone rotating member up to the rotative speed of another before effectinga connection between them, thus clashing. An automatic means ofoperating this synchronizer is combined to act in timed relation withthe automatic mechanism for operating the two clutches in the ilywheel.All of the above transmission mechanism is particularly adapted forautomatic operation by fluid pressure mechanism to which novel additionshave been made over my previously designed units.

It ls therefore a primary object to provide a compact transmission unitadapted for automatic operation in which two or more clutches areengaged alternately to establish driving connection through two or moregear trains and to provide means for automatically altering the ratiothrough one (or both) of the gear trains While the other is inoperation. f

It is a further object to provide a gear changing mechanism to alter theratio through one (or both) of the drives established by the alternatelyoperated clutches, the said gear changing mechanism to be automaticallyoperated by fluid pressure mechanism operating in timed relation withother fluid pressure mechanism used to actuate the clutches.

It is a further object to provide fluid pressure operated controlmechanism for actuating a transmission, having means incorporatedtherein for controlling the rate of actuation of the several parts ofsaid transmission in such manner as to properly time the operation ofthe several parts thereof.

It is another object to provide a gear changing mechanism of the typeemploying a synchronizing means for bringing rotating parts to the samerotative speed before effecting positive connection thereof, withautomatic means for operating said mechanism including means to eiect apause in the movement of the actuating mechanism during the time theparts are being brought to the same rotative speed, followed by a rapidmotion of the actuating mechanism to complete the positive connection. v

It is a further object to provide a fluid pressure mechanism foroperating a gear changing mechanism of the synchronizing type which willproduce a desired variation in the rate of movement of its operatingparts by control of the flow of fluid under pressure.

It is another object to provide for the control of a gear changingmechanism of the synchronizing type using fluid pressure for itsoperation so arranged that the full pressure available in the fluidpressure system will be effective to actuate the mechanism, means beingprovided to completing the connection without objectionable drain 011uid Which leaks past the actuating parts, thereby to prevent building upof pressures in other parts o! the system which would oppose movement ofsaid actuating parts.

It is a further object to provide a iluid pressure operated clutchactuating unit which will be enective to prevent too sudden release ofthe clutch by provision of means to control the iiow of iluid on releaseof pressure from said clutch control unit. Such a type of control (1)prevents jerky shifting due to sudden release of the driving torque; (2)holds the engine speed down during the time when the change in gearratio is made; (3) prevents full release of the driving torque duringthe period when change in gear ratio is being effected.

It is another object to provide means in the fluid pressure controlmechanism for applying iluid under pressure to actuate a clutch in suchmanner as to actuate said clutch slowly when used for shifting intolower gear so that the high torque transmitted at this time will notjerk the car.

It is a further object to provide means to prevent the automatic controlmechanism for operating the transmission from changing the transmissiongear ratio from the low speed to the high speed position when thetransmission is set for reverse operation.

It is another object to provide means whereby an auxiliary pump foremergency use may have some of its parts used in common with some unitof the fluid pressure system.

It is a further object to provide an auxiliary pump combined with anaccumulator piston in the fluid pressure system whereby a pumping actionis effected by the reciprocating motion of said piston, saidreciprocating motion being effected by a repeated operation of a clutchpedal located in the drivers compartment of the vehicle.

It is also an object to provide means for directing fluid under pressureto several operating units thereby to selectively operate a plurality ofclutches and a synchronizer shifting unit in timed relation with eachother.

It is another object to provide means for preventing the iluid pressureoperating mechanism from changing the clutch connection before thesynchronizer unit which has started its movement has eifected positiveconnection between the rotating parts.

It is a further object to provide for clutch operation by fluid pressureactuated mechanism reacting and contained in a member rotating` with theclutch, the rotating member being supported for rotation in a stationaryhousing, which housing also has means provided therein for feeding fluidunder pressure for operating the clutch.

It is another object to provide iluid pressure operated mechanism,having the advantageous feature of rotation with the clutch, with meansfor preventing uid used to actuate said fluid pressure mechanism fromreaching the contacting parts of said clutch.

It is a further object to provide a mounting for a fluid pressureoperated clutch operating member flexibly supported in the housingrelative to the clutch and relative to the other parts of thetransmission, thereby to allow for misalignment of parts.

It is another object to provide fluid pressure mechanism for operatingthe clutches, rotating with said clutches and flexibly supportedrelative to the transmission and clutch mechanism, said rotatingmechanism also being used to carry a.

Journal for a sleeve which connects one of the clutches with certain ofthe transmission gearing. 'I'he above and other objects of the inventionwill appear more fully from the following detailed description of apractical embodiment of the invention and by reference to theaccompanying drawings forming a part hereof and wherein:

Fig. 1 is a vertical section through a completely assembled transmissionunit showing the general arrangement of the several parts.

Fig. 2 is a diagrammatic view showing particularly the arrangement ofthe iiuid pressure mechanism for automatic operation of the transmissionunit.

Fig. 2a is a view taken substantially on the line 2li-2a of Fig. 1showing, particularly the position of the fluid pressure controlmechanism housing at the side of the transmission unit.

Fig. 2b shows mechanism for producing slower operation of thetransmission when the toebutton control is actuated to shift thetransmission to a lower speed.

Fig. 2c shows mechanism used to assure rapid build-up of pressure duringthe iirst part of the time used to actuate the clutches followed by aslow build-up of pressure near the end of the time required to actuatethe clutches.

Fig. 3 is a section taken substantially on the line 3-3 of Fig. 2a andshows a. section through the uid pressure control unit and discloses inpartial detail the accumulator piston, the pressure control valve, theselector valve and the differential lever.

Fig. 4 is a horizontal section taken substantially on the line 4--4 ofFig. 2a and shows particularly the mechanism for automatic operation ofthe synchronizer unit.

Fig. 4a is a view of the synchronizer operating piston and cylinder andshows particularly the fluid pressure conduit system for operating thisunit.

Fig. 5 is a vertical section taken substantially on the line 5-5 of Fig.3 and shows a crosssectional view of several of the huid pressurecontrol units.

Fig. 6 is a fragmentary sectional view taken substantially on the line 66 of Fig. 3 and shows an end view of the lever mechanism shown in theside view of Fig. 3.

Fig. '1 is a top fragmentary sectional view taken substantially on theline 'l-l of Fig. 1 and shows a part of the connecting linkage betweenthe vehicle speed responsive governor and the differential lever.

Fig. 8 is a fragmentary section taken substantially on the line 8-8 ofFig. 7 and shows further details of a. part of the linkage connectingthe governor and the diti'erential lever as well as the shifter forksfor operating the synchronizer unit and reverse drive.

Fig. 9 is a view intended primarily to show the means for rendering theautomatic gear shifting mechanism inoperative when the transmission isset in reverse drive position; the view showing the parts as they wouldbe seen from the top of Fig. 8 with a portion of the housing removed andalso partly broken away.

Fig. l0 is a section taken substantially on the line Illl0 of Fig. 7 andshows details of the lever mechanism connected with the governorcontrol.

Fig. 11 is a section through a clutch plate and facing showing aresilient mounting between a clutch plate and its facing.

Fig. 12 is a view taken substantially on the line I2-Iz of Fig. 11 andshows further details of the resilient member between a clutch facingand a clutch plate.

GENERAL Anmncamr Referring to Fig. 1 there is shown a section through atransmission disclosing the general arrangement of the gear and clutchunit together with a portion of the iiuid pressure mechanism andcontrols.

The general scheme of the arrangement shown in Fig. 1 requires twoclutches III, II, which are enclosed within a ily-wheel I2, the combineddesign of fly-wheel and clutches being so worked out that the size ofthe ily-wheel unit is not increased unduly by the addition of the twoclutches. By a fluid pressure mechanism designated generally as I3 whichis designed to rotate with the fly-wheel the clutches I and II areactuated to either connect the engine driven ilywheel I2 to a main shaftI4 or to a sleeve I5. The sleeve I5 has a gear I6 attached at its outerend. The main driving shaft `I4 extends entirely through thetransmission and, therefore, when the engine driven iiy-wheel isdirectly connected with shaft I4 by means of the clutch II a directdrive is effected. Normally free to rotate upon shaft I4 are providedtwo gear units, i1 and I8, which may be selectively connected to rotatepositively with shaft I4 by means of synchronizer unit I9.A'counter-shaft 2I is provided below the main shaft I4 and has mountedthereon a gear 22, which is constantly meshed with gear I6 of the sleeveI5. Also mounted on countershaft 2| and formed integral with gear 22 isa gear 23 which is in constant mesh with gear l1, which may be connectedwith drive shaft I4 by I synchronizer I9. Gear unit I 8 is of spoolshape and has two gears at the ends thereof, namely 24 and 25. Connectedto counter-shaft 2l by suitable splined connections so as to rotatetherewith but free to slide lengthwise thereof, are a pair ofgears 26,21, adapted to be actuated for sliding movement by forkl 28, a portionof which is shown in Fig. 1. When the gear unit 26, 21 is moved to theright along shaft 2|, as shown in Fig. l, the gear 26 will mesh with thegear 24 and on still further movement toward the right, the

. gear 21 will mesh with the gear 25.

As the gear and clutch set up is shown in Fig. 1 and using the partsabove described, the device operates substantially as follows: For lowgear the gear unit 26, 21 is moved to maximum distance to the right sothat gear 25 is in mesh with gear 21. The clutch Ill is actuated by thefluid pressure mechanism, later to be described, and the engine drivenily-wheel I2 is thereby connected with the sleeve I5 causing rotation ofthe gear I6. The gear 22 is driven by gear I6 and rotates shaft2|,vcarrying gear 21 which meshes with gear 25 on shaft I4. Since atthis time the synchronizer I9 has been moved to connect gear unit I8and'gear 25 to the shaft I4, the drive is completed.

For second speed, the gear 26 is nrst put in mesh with gear 24 and thesame gearing above described effects second speed. For traiiic drivingthe manually moved gears 26, 21 are left in position so that the gear 26is meshed with the gear 24. The automatic control of the device is usedto change the gearing from the normal second speed to direct drive andthen to over-drive. This is accomplished by a iiuid pressure unit whichmoves the synchronizer I9 in timed relation with the ui'd pressure lunitwhich engages and disengages clutches I0 and II at the proper time.

The shift from second speed, to the next higher ratio of direct drive iseffected by the fluid pressure mechanism ilrst actuating the clutch IIto connect the y-wheel I2 directly with the shaft I4, and releasingclutch III, thereby removing the driving load from the low gear trainand synchronizer and applying it directly to the shaft I4. The next stepis to actuate the synchronizer I9 by moving the collar thereof towardthe left as shown in Fig. 1. This movement disconnects the gear unit I9from the shaft I4 and effects connection of gear I1 to said shaft I4.

Ihe change from direct drive to overdrive is effected by disconnectingclutch II and connecting clutch I0, the synchronizer I9 having beenpreviously actuated to connect the gear I1 to the shaft I4. The drivethen is through sleeve I5, gear I6, gear 22, gear 23, gear I1 and outthrough shaft I4.

The arrangement of clutches and gearing makes it possible to haveclutches which are engaged alternately to establish driving connectionthrough various drive ratios and means for automatically altering theratio through one of them while the drive is through the other.

It is understood that the automatic mechanism for effecting thesechanges is controlled by other automatic units later to be describedlbut the present description is for the purpose of showing the generalscheme of gear, clutch and synchronizer set-up.

The movement of the gears 26 and 21 along shaft 2| is intended to bemanual and there is also provided a reverse counter-shaft 29, with asuitable gear 29a (Fig. 8), with which gear 26 may -be meshed bymovement toward the left from the position shown in Fig. l.Thereforewith the manual movement of the gear unit 26, 21 alongcounter-shaft 2l it is possible to effect reverse drive or to set up theunit for starting in either low or traffic second speed. For ordinarycity traflic driving the unit would be left in the second speed positionand automatic operation would be effected from second through directdrive and then into over-drive, thus affording three automatic speeds.It is, of course, apparent that the gear unit could be designed toprovide three automatic speeds of any desired ratio with possibility ofchanging one of these speeds to a different ratio by manual operationand, in addition, to provide a manually controlled 4 reverse.

It is particularly to be noted that this transmission set-up makes itpossible to disconnect the lower drive ratio gears from the propellershaft when the higher ratio gears are in operation, thereby eliminatingthe idle running of the low speed clutch and gearing at excessive speedsduring high speed operation. This feature is noted with reference toFig. l where it is apparent that when the unit is in overdrive posi'-tion, where it remains for a major portion of the time, the gear unit I8will be disconnected from shaft I4. Gear unit I9, shaft 2l and gears 22,

23, 26 and 21 are then driven at relatively low As previously mentioned,the mechanism for operating the clutches and of the transmission ismounted for rotation with the flywheel and clutch unit. The mechanism isfluid pressure operated and comprises a plurality of' pistons andcylinders mounted in a member 38 which is of such shape as to be mountedupon and surround the sleeve member I5, a projecting circular portion ofthe member 30 providing space for six horizontally disposed cylindricalopenings, three of these cylinders with suitable pistons being used foractuation of the clutch I and the other three being used to actuate theclutch II. The member 30 is secured to rotate with the flywheel I2 andsecured from endwise movement by screw 30a. shown in Fig. 1. The sixcylinder and piston units may be spaced around the member 30 in anysuitable position so that three equally spaced lever units for eachclutch may be actuated. There is shown in Fig. 1 one cylinder unit 3|for actuating the clutch I0 and also one of the three cylinders 32 foractuating the clutch I. It is understood that the other two units ofeach set are of similar construction. Considering the actuating unit forclutch I0, a piston 33 is mounted in the cylinder 3| withsuitableconnections to a lever 34 which is pivoted at 35 and actuates arod 36 connected with the clutch I0, as shown. It is therefore apparenton inspection of Fig. 1 that a movement of the piston 33 toward the leftwill move the connecting linkage in such direction as to engage theclutch I0 and thereby connect the engine driven flywheel I2 to rotatesleeve I5. Similarly, the other set of cylinders will actuate the clutchI I through a piston 31, a lever 38 pivoted at 39, and a connecting rod40. It is noted that the lever 38 is so pivoted relative to the rod 40that movement of the piston 31 pushes the rod 40 toward the left, asshown in Fig. l, which direction of movement actuates the clutch andconnects the flywheel I2 to rotate the shaft I4. It is an importantfeature of the above described construction that the endwise reactionfrom the pistons is transmitted to the flywheel through the connectioneffected by the set screw 30a and snce the whole clutch operating unit30 rotates with the flywheel the endwise reaction from this unit is nottransmitted to the bearings of the transmission or engine.

Transmission operating mechanism.

There is shown in Fig. 2 a diagrammatic view of the several units of thefluid pressure control mechanism which make up the unit for automaticoperation of a transmission of the general type just described. In themechanism illustrated in Fig. 2 there is provision for operation of twoclutches, one of which operates a first and a third speed, and the otherof which operates a second speed, these clutch operating members beingdesignated as pistons |2| and |22. The synchronizer shifter fork |23 isfor the purpose of changing the connection from first to third speedwhile the second speed clutch piston |22 is in operation.

It is understood that the first, second and third speeds as designatedabove might be the second, direct and overdrive ratios respectively asdisclosed in the transmission shown in Fig. 1 and previously described.Obviously however, the same type of operating mechanism as hereindisclosed might well be used to operate a transmission having theconventional low, intermediate and high speed ratios.

The mechanism for automatic operation is actuated by fluid underpressure. A pump |24 is driven from the engine of the vehicle and drawsoil from a sump provided in the lower part of the transmission throughan intake conduit |25, fluid under pressure being delivered to a pumpoutlet conduit |25 which leads to accumulator chamber |21. A springloaded accumulator piston |28 is mounted for operation above theaccumulator chamber |21 and serves to limit the maximum pressureavailable in the accumulator chamber by provision of a by-pass |23 whichleads to the sump and which is in a position to be opened when thespring loaded piston |28 passes a definite position. An out t |3| fromthe accumulator chamber is provided and a check valve |32 allows one waymovement of the oil from the accumulator chamber |21 into conduit |33.

For the purpose of providing a variation in the size of the conduitleading from the accumulator chamber a Jet changer |34 is provided. Thisunit comprises a sliding member I 36 with various sizes of openingstherein, and in the particular unit used for illustration there is alarge opening |31 and a small restricted opening |38. The small orifice|38 is placed in position for operation when it is desired to have aslower clutch engaging movement of' the device and the largerunrestricted opening |31 is used when faster clutch engaging movement isdesired. The continuation of the conduit |33 is here shown as a smallerpassage |33a which leads to the inlet opening |33 of a pressure controlvalve |4I. 'Ihe smaller size of conduit I33a results in a slow fluidflow when the fluid is cold as in starting with a cold engine.

The function of the pressure control valve I4| is to provide requiredvariation in the pressure of the oil used to actuate the clutchoperating pistons |2| and |22. It is to be understood that for mosteflicient clutch engagement there is of necessity a lower operatingpressure required at small throttle openings than is required at greaterthrottle openings. The pressure control valve is connected to thethrottle control by a stem |42 which abuts at its lower end with a plug42a engaging the upper end of a spring |43 mounted in the bottom of thepressure control valve cylinder. With the opening of the throttle thestem |42 is pressed downwardly thereby reducing the tendency of spring|43 to compress spring |43a, thus relieving the pressure on valve |44and permitting the fluid pressure in conduit |46 to increase. The upperend of the pressure control valve has a valve member I 41 held by aspring |48 to close the end of a sump outlet opening |49. Springs |48and I43a are of such strength that valve |41 will always hold anypressure admitted through valve |44 but provides an outlet to reduce thepressure in conduit |43 when the throttle is released. With increase inthrottle opening the downward movement of the valve stem 42 reduces thecompression of inlet valve spring |43a and increases the compression ofoutlet valve spring |48, thereby allowing maximum pressure available tobe fed into conduit |48 and held there. However, when the throttle isnear its closed position outlet valve spring |48 will be less compressedand will allow valve |41 to release, thereby providing a lower fluidpressure in conduit |46 at small throttle openings.

As shown, there are three separate outlet conduits branching from theconduit |48, i. .e., IBI, |52 and |53. These conduits are positioned toopen into a selector valve cylinder |54 in which a selector valve member|56 is mounted for sliding movement.

Although the design of selector valve shown herein provides some newfeatures, the general arrangement of the valve and its housing aresimilar to that employed in my co-pending applications, Serial Nos,584,812 and 715,065, and in my United states Pai-.ent No. 2,019,146. 1nthey constructions described in the above applications iluid underpressure is fed to desired units by positioning the valve to connectports which open into the valve cylinder, suitable annular rings beingcut in the valve body to connect the inlet ports with outlet ports onthe opposite side of the valve cylinder when the valve body is in properalignment.

The mechanism for positioning the selector valve will be describedlater. For the present it is sufficient to state that means is providedto move the valve body I 56 progressively upward, as shown in Fig. 2,when it is desired to shift through the available range from lower tohigher gear ratios and in opposite direction to shift from higher tolower gear ratios. This positioning mechanism, as will later appear, ispreferably automatic in operation, but it is to be understood that manyadvantages of the iluid pressure operating mechthe conduits |62 and |53,thereby effecting a connection between these two conduits and allowingfluid under pressure from conduit |46 to be admitted to conduit |62 andthence into cylinder |59a to actuate piston |22 which engages the secondspeed clutch. By the movement of the se'- lector valve member |56 justdescribed there has been effected a reversal of the clutches, i. e.,clutch operating piston |2| has thrown its clutch out of engagement andclutch operating piston |22 has had the pressure admitted to itscylinder to engage the clutch attached thereto.

'As the car increases in speed the control mechanism continues to movethe selector valve in an upward direction. Adjacent the last mentioneddrilled opening |64 in the selector valve |56 there is provided anannular groove |66 which is similar to the groove |51 but of greaterlength. The groove 66 is of such length and position that when its upperedge comes into alignment with the conduit |58 it bridges the conduits|5| and |52 so that there is an unrestricted flow of fluid underpressure into the conduit |58 to again actuanism would remain regardlessof the means used to position the selector valve.

Continuing with the description of the showing in Fig, 2, the outletconduits |5| |52 and 53 are spaced along, and open into, the selectorvalve cylinder |54. 'Ihe body of the selector valve member |56 has anannular groove |51 cut in its periphery and the valve member |56 isshown positioned to connect, through this groove |51, the outlet conduit|52 with the conduit |58 on the opposite side of the selector valveopening. The conduit |58 leads directly to cylinder |59 for operatingthe clutch operating piston |2|. As'here shown, the piston is beingactuated to operate the clutch to effect rst or low speed of thevehicle. Also inthe selector valve member |56, a drilled opening |6| isprovided which opens into the hollow central piortion of the selectorvalve member |56 and connects to the sump. The drilled opening |6| is sopositioned when groove |51 connects conduits |52 and |58 as to alignwith a conduit |62 which is connected to a cylinder |59a for operationof another clutch operating piston |22. The alignment of opening |6|with conduit |62 connects cylinder |5911 with the sump and releases allpressure therein and it follows that the clutch which is operated by thepiston |22 must then of necessity be disengaged.

It is noted that the conduit |52 is provided with a restricted openingfor the purpose of effecting a slow engagement of the rst or low speedclutch to simulate the conditions found most advantageous for thisoperation.

Also provided in the selector valve member |56 is a drilled opening |64which is Vmore restricted than the similar opening |6|. Like the opening|6|, the opening |64 connects the outside of the selector Valve member|56 with its hollow central portion and is so positioned that when theselector valve member |56 moves upwardly the drilled opening |64 is inalignment with the conduit |58 leading to the cylinder |59 of the iirstspeed clutch piston |2 This connection results in the release ofpressure in said cylinder |59 through the restricted opening |64 therebyeffecting a slow release of the rst speed clutch. The same upwardmovement of the selector valve member 56 causes the annular groove |51to come in alignment with ate the piston I2 I this time for a third orhighest speed operation, the ratio of the gearing having been changed bythe operation of the shifter fork |23 in a, manner winch will beexplained presently. The reason for the bridging of the conduits |5| and|52 by the longer annular opening |66 is because it is not desired tohave the inlet of fluid under pressure to actuate this clutch for thirdspeed to be a restricted or slow movement as was the case when the sameclutch was previously actuated from the conduit |52 alone for rst speed.The same movement of the selector valve rnernber |56 which bridges theconduits |5| and |52 by annular opening |66 and connects them withconduit |58, places the restricted outlet conduit |64 in position torelease pressure from conduit |62, thereby eiIecting a gradual releaseof piston |22 and the clutch connected therewith. The positioning of thevarious annular grooves of the selector valve and the provision ofrestricted and unrestricted openings positioned as above describedresults in a proper timing of the operation of the clutches by providingthe required amount of overlap between the actuation and release ofconsecutively operated clutches, thereby preventing both racing of theengine and objectionable jerking of the car.

There has been described above the mechanism which first actuates thefirst speed clutch, then throws it out of engagement and actuates thesecond speed clutch, then releases the second speed clutch and actuatesthe rst mentioned clutch a second time, this time for third speedoperation. The mechanism for operating the synchronizer which makes itpossible to change the gearing connected with the rst and third speedclutch so that this clutch may be used for the dual purpose mentionedwill now be considered.

synchronizer operating mechanism The uid under pressure for theactuation of the synchronizer operating mechanism does not come throughthe pressure control valve as does that used for actuating the clutches,it being unnecessary when shifting this unit to change the pressure forvarying degrees of throttle opening. For eilecting this result a conduit|1| leads directly from the accumulator chamber |21 and connects withthe conduit |12 which leads to two selector valve inlet ports |13 and|14. Fluid under pressure from the accumulator chamber is thus madeavailable at the selector valve. In

the position shown in Fig. 2 pressure from the conduit |14 is beingallowed to enter a conduit |16 because of the alignment of an annulargroove |11 in valve member |56 with the conduits |18 and |16. At thesame time a drilled opening |18 leading into the center of the selectorvalve member |56 is placed in communication with a conduit |19, therebyconnecting said conduit |19 with the sump and releasing all pressuretherein. As shown in Fig. 2,`conduit |16 leads to one end of acylindrical chamber |8|, the conduit having means to provide arestriction to flow in the direction away from the cylindrical chamber|8| but to allow free passage oi' fluid in a direction toward saidchamber. This result is accomplished by a star-shaped orice membermounted in the conduit as indicated at |82 so that movement of uid inthe direction toward the chamber |8| allows the orifice member tolift-olf its seat and allow free passage of the fluid under pressure,while in the opposite direction the orifice member is seated andprovides a restriction in the conduit |16.

The conduit |19 previously mentioned leads to the opposite end of thecylindrical chamber |8| and is similar in shape and configuration toconduit |16, there being an orice |88 similar to |82 which providesrestriction to flow away from cylindrical chamber .|8| and unrestrictedflow toward said chamber. A synchronizer operating piston |84 is mountedfor reciprocation in cylindrical chamber |8| and by its reciprocationmoves the synchronizer operating shaft |85 on the end of which ismounted the previously mentioned synchronizer shifter fork |23. From thegeneral lay-out just described, and by-reference to Fig. 2, it isapparent that the piston |84 is moved in one direction by admission offluid under pressure through conduit |19 and in the opposite directionby admission of fluid under pressure through conduit |16 When one ofthese conduits is connected to the pressure line the other must ofnecessity be connected to the sump so that oil in the low pressure endof the cylinder .will be allowed to flow out. For the purpose ofcontrolling the movement of the piston |84 the previously mentionedorifices |82 and |88 actin such manner that there is a restrictionto owof fluid out from the cylinder 8| while the fluid under pressureentering the opposite end of the cylinder is always allowed to enterunrestricted. 'Ihis feature is considered important since it allowscontrol of the rate of movement while still maintaining full pressure onone end of the piston. In this connection an important and novel featurehas been incorporated in the design of the synchronizer operating pistonby provision of an annular groove |84a around the central portion of thepiston, this annular groove being drained to the sump through an opening|84b in the casing of cylinder I8 l. It has been found that such aconstruction is very advantageous. Since the control of iiow is effectedby a restricted orice on the outlet side of the piston, if fluid underpressure from the inlet side should leak past the piston it would have adirect effect on the rate of movement of the piston, and would produce aback pressure against the outlet side of the piston. However, if leakagefrom the inlet side is drained oil' at the center, the restricted outletis free to control the movement without any detrimental build-up ofpressure by leakage past the piston. In this way full pressure from theinlet to move the piston is assured, Whereas if the leakage were allowedto build up on the outlet side the full inlet pressure would not beavailable because it would be partly offset by leakage pressure on theopposite side of the piston.

Considering the operation of the synchronizer shifting unit inconnection with the mechanism for operating the clutch pistons |2| and|22 previously described, it is apparent because of the positions ofgroove |11 and drilled opening |18 relative to conduits |16 and |18 thatthe syngroove |86 will connect the pressure line with conduit |19.Because of the admission of fluid under pressure through said conduit tothe lower end of cylindrical opening |8|, the piston |84 will be movedin an upward direction carrying with it the synchronizer operating shaft|85.

The ports and grooves of the selector valve for operating the clutchesand the synchronizer are so positioned relative to each other that onupward movement of the valve member |56 the previously described releaseof pressure on piston |2| and the admission of pressure to piston |22are both effected before the pressure is reversed on the synchronizercylinder to start its movement in the opposite direction. When thesechanges in pressure flow have been accomplished and the synchronizerpiston started on its travel it is necessary that pressure conditionsremain unchanged until the shift of the synchronizer is completed,because power applied by the clutch engaged by piston |2| is transmittedthrough the synchronizer, and should this clutch be engaged while thesynchronizer is in motion, damage would result. Satisfactory operationis assured by the provision of interlock pins |81 and |88 which serve tohold the selector valve member |58 from further movement until thesynchronizer piston has reached its maximum movement and completed itswork. Two recesses |89 and |88 in the synchronizer operating shaft arepositioned to allow the pins |81 and |88 to move backwardly away fromannular projections |8| and |92 when the synchronizer shaft |85 reachesthe end of its travel. The two interlock pins |81 and |88 are spaced asshown in Fig. 2 for the reason that one of them acts when thesynchronizer I movement is in one direction and the other when themovement is in the opposite direction, the relative positioning of thepins and the projections being such as to effect the required fixedpositioning of the selector valveduring the time necessary to completethe synchronizer shift. When the synchronizer operating shaft comes tothe end of its travel in either direction, pin |81 or |88 drops into theslot and away from the proection against which it has been riding, andthe selector valve is again free to move and on further upward movementwill change the alignment of the drilled openings |6| or |64 and theannular groove |51 to reverse the pressure conditions in the conduits|58 and |62. thereby to put the opposite clutch |2| in operation foreffecting the third forward speed.

A control cable unit |83 is used to connect the sliding member |36 ofthe previously mentioned jet changer |84 with the end of thesynchronizer operating shaft. By this connection large less restrictedopening |31 is placed in positionfor'.

communication with the conduit |29-when the synchronizer is in positionfor low speed, as shown in Fig. 2, while in the opposite position ofthesynchronizer the action of the control cable isto' move the slidingmember |36 of the jet changer nectedV actuatecthe Ypressure controlvalve y through rodk |42, the ythermostatic element 9| will .vary ,the`relativeposition between the andthe units it controls.v

throttle with the use or the throtue as one of the ele-v-"'.mentsfor-controlling the automatic transmission to place the morerestricted opening `|99 in position for operation in the conduit |33,the effect of it follows that thevv operation of the accelerator pedal92 will automatically operate the fluid pressure control lsystem for thetransmission, and it I canjbe imagined that this would not be alwaysdesired. In lorder to provide an independent control of the enginethrottle which willnot also operate the transmission control mechanism,a separatehand throttle unit 90 is provided, as shown in the upperportion of Fig. 2. This hand throttle control is connected to a separatethrotfrom rst to second, which must'l be mad-i' l promptly to preventthe engine from racing unduly during the shift. It is to be noted thatwhen shifting from a high gear to a lower one, the a engine mustincrease its speed, whereas when shifting from a low to a higher gearvthe-engine speed must be decreased by the clutch application.V The jetchanger connected as shown provides proper time intervals for the upshift from first to second and the down shift from third to sec- -tle`lever 9| by control cable 92. The lever 9| actuates the throttle withoutmoving the rod 90 or the accelerator pedal and its connection |95 to thetransmission operating mechanism. There is thereby provided an'independent control of the engine throttle, f

A clutch pedal A|99 is shown with a lever 200 attached thereto formanual actuation of the accumulator piston |29. By inspection of Fig. 2it is apparent that downward pressure on the clutch pedal such asnormally would be used to throw j out the clutch-in a conventionallycontrolled car will 'resultin moving the accumulator piston upond. Itseffect on the other. shifts is relatively unimportant.

Further details of the synchronizer operating piston and its springconnected synchronizerop. erating shaft |85 will be considered when theactual unit'is described in another section. t It is also to beunderstood that the term synchronizer as used in the above descriptionmight well include several different types of mechanism for changinggear ratio by a transverse shift of a member such as shown at |23.

In the upper portion of Fig. 2 there are shown certain controlmechanisms. The general arrangement of the control for actuating theselector valve by the combined or differential action of vehicle speedand throttle control position, although including certain additional andnovel features, isslmilar to that described in my co-pendingapplication, Serial No. 603,823. There is shown in Fig.2 a governor |94driven at vehicle speed which actuates one end of a differential lever|96 and a throttle and foot accelerator unit which through rod |95actuates the opposite end of the differential lever |96. The lever |99is pvoted on the selector valve control rod |91 and thereby the selectorvalve is positioned by the differential effect of throttle controlposition and vehicle speed. v

The carburetor and throttle unit of the engine is shown at |98 withconnection to the throttle for both hand operation and foot accelerator.The connection between the accelerator pedal and the throttle iseffected by a rod 60 in which is incorporated a thermostatic element 6|.The bell crank lever 62 connects the rod 60 with the vertical rod |95which connects with the differential lever |96. The use of thethermostatic ele'- ment 6I in the connection between the throttle andthe differential lever, as above outlined, provides an automaticadjustment for variation with temperature which is very important foruse with hydraulic operated transmissions depending on the throttle forcontrol. In the present case the throttle being connected to actuate oneend of the differential lever |99 and secondarily conward a'suiilcientdistance to open the by-pass |29 and :release pressure from theaccumulator chamber |21 and therefore release the pressure in thesystem'and disengage any clutch which may be in engagement. In otherwords, the same result as in conventionally controlled cars isaccomplished by the downward pressure of the clutch pedal, i. e., thethrowing out of the clutch. y

The connection of the clutch pedal to the accumulator piston servesvanother purpose, namely, that of an auxiliary pump for emergencyoperation when required. This result is accomplished by working theclutch pedal up and down and thereby reciprocating the accumulatorpiston |28. Because of the provision of a check valve 20| oil is drawninto the accumulator chamber |21 from the sump and the pressureincreased in the chamber to a sufficient amount for emergency operationof the device. Y

1 Near the accelerator pedal in Fig. 2 there is shown a second and firstgear toe-button 202 which is used 'to hold the upper end of the selectorvalve control rod` in position so that'I it will not shift out of secondor first gear as may be desired depending upon 'the amount of movementgiven to the toe-button 202.

As shown in Fig. 2b, it is intended to incorporate with the toe-buttoncontrol 202 a means to change the rate of clutch application for thepurpose of effecting a" slower build-up of pressure when the shifting bymeans of the toe-button is from a higher speed to a lower speed, such asis the condition when shifting down to the second speed position to usethe second gear for the purpose vof retarding the motion of the car. Asshown in Fig.` 2b, this is accomplished by two sizes of jets' interposedin the fluid pressure system ind controlled by the rod 63 which isactuated by the movement of the toe-button 202. The conduit 91 leadsfrom the accumulator cylinder and branches into conduits and 66 whichare connected with the vertical opening 68, the outlet to the pressurecontrol valve being shown at V'69. The rod 63 controls a piston member64 v'hich covers an unrestricted opening in conduit 6b and forces theliquid to go' through a restricted jet inFig. 1. `if

B. Therefore, whenever the' toe-button 202 is depressed to hold thetransmission in the second speed position the piston 64 will cover theunrestricted opening and force the fluid pressure to flow through therestricted jet 00 'and .therefore produce a slower operation of thetransmission.

Although in Fig. 2b the rod 63 which controls the closing of vtheunrestricted opening 65 is shown operated by the toe-button 202, such aunit might also be set up to be actuated` by the vehicle speed governorand when so connected would provide means to assure slower operation ofthe fluid pressure actuating mechanism at higher vehicle speeds therebyincreasing the time required for clutch application at the higherspeeds. The unit shown in Fig. 2b actuated by the governor 202er asshown in Fig. 2d would be in a position to furnish unrestricted ow ofiluid under pressure at low speeds, but as the speed of the governorincreased would close the opening 05 and thereby require sloweroperation by forcing the iluid under pressure to go through therestricted opening 06. Similarly, it might be possible to actuate theunit by means of a thermostatic element 202b as shown in Fig. 12 andthereby vary the time required to actuate the clutches in proportion t'otemperature conditions.

It has been found in operation of fluid pressure transmissions of thistype that it is important izo-provide means between the pressure controlvalve and the selector valve to allow the pressure to build up veryquickly at the beginning of any clutch application, but as the maximumpressure actuatingthe (clutch is approached it is very advantageous thatthe pressure then build up more slowly. 'I'his is accomplished by themechanism shown in Fig. 2c wherein conduit marked leads from thepressure control valve .and branches into conduit 1| having a largeopening provided with a ball check valve 12 retained by a spring 13.'I'he other branch of the conduit lla contains a restricted orice 14.The

two branched conduits both connect into the conduit 15'which leads tothe selectorvalve. In the branched conduit 1l in which is incorporatedthe large orice and `the spring' retained ball vcheck valve, the spring13 is so selected as to hold the check valve closed to a :pressure alittle under Athe maximum pressure which is desired. There-l I fore. atthe beginning of any pressure change the high pressure which isnaturally thrown intothe conduit 1| will hold the.ball check valve 12open The mechanism will be described under the following headings:

(a.) Fluid pressure pump;

(b) Accumulator;

(c) Pressure control valve;

(d) Selector valve and connections to actuating units; y

(e) Synchronizer control cylinder and control parts to connect withSynchronizer;

(f) Synchronizer and selector valve interlock;

(g) Governor;

(h) Controls from governor and throttle to differential lever;

(i) Reverse interlock;

(i) Clutch operating mechanism and support in transmission housing;

(lc) Detals of clutch construction to adapt for automatic operation.

(a) Fluid pressure pump Referring to Figs. 1 and 5, it is noted that ailuid pressure pump numbered is mounted in the lower central portion ofthe transmission housing. This pump, as shown in Fig. l, has attached toits shaft a gear 5I which is driven from a gear 52 attached to a sleeveextension of the rotating housing provided for fluid pressure mechanismI3. This entire unit, it will be remem-A bered, rotates with the enginedriven flywheel l2 and therefore rotates at all times when the engine isoperating. 'I'he detailed construction of the pump, which is of the vanetype will not be considered in detail here as it forms no part of thepresent invention.

The outlet from the pump 50 is connected by a conduit 200 to dischargefluid into accumulator cylinder 20] (Fig. 5).

(b) Accumulator l accumulator cylinder is maintained at a pressure n andallow flow through the unrestricted opening l and thepressurewill-.therefore build up quickly. However, asthe. pressurebuilds up in the conduit 15 and-the maximumiprssure is approached the,`

spring `13 will causethe :ball check valve to be closed and force vtheflow to'gothrough the restricted jet nandtherefore during the remainingtime of the-build-upltotherdesired maximum the changewillbe a slowerone. g l

The 'basic featuresfofl-the ilu'idpressure mech? to'a practicalstructure. and also to disclose cer-` tain additional novel features ofthe device', there.

is shown in thedrawing's and described herein after a mechanism suitablefor actual operation and assembly with the transmission unitfshownydetermined by spring 2H and when such pressure exceeds a denite amountthe fluid is bypassed to limit the pressure accordingly.

As shown in Fig.V 3, there is provided a shaft 2H which is secured tothe piston 209 and projects outwardly of the housing as shown. Whensuitable actuating means are provided for this shaft it is possible touse the accumulator piston as an auxiliary pump. For such use the pistonis reciprocated and draws oil` from the sump at 203 through' check valve.204 into conduits 206 and 208 and thence into the cylinder 201 (seeFig. 5,).

At the top of the accumulator cylinder 201 see y .Y Figs. r3 and`5)there is provided an outlet conduit 2|0 (see Fig. 5) from theaccumulator in which v`vconduit is a ball check valve 2I9. This conduit2 I 8 connects with a pressure conduit 22| (see Figs. 3A and 45) whichcarries the fluid under pressure from ,the accumulator cylinder to aconduit 222 having a restriction therein (see Fig. 5) which opens intothe pressure control valve cylinder 223.

(c) Pressure control valve The function of the pressure control valve isto provide for changes in the pressure of clutch application betweenllarge and small throttle opening positions. This valve, therefore,controls the pressure of the uid fed to the selector valve for use inactuating the two clutches I and The pressure control valve is providedwith a cylindrical body portion 224 (see Fig. 3) on the central axis ofwhich is slidably mounted a valve stem 226. This valve stem has slidablymounted thereon two valves 221 and 228 which arev seated in the oppositeends of the central opening through the vbody portion 224. Toward theright hand end of the valve cylinder there is provided a cylindricallyshaped abutment member 229 which has a recess 23| in its inner end, theabutment portion 229 extending outwardly from the cylinder opening. Thevalve stem 226 has an extension which abuts against the base of theinner recess l23| and there is provided a spring 232, one end of -whichreacts against the inner face of the recess 23| and the opposite endagainst the valve 228. In the opposite end of the valve a spring 233 isso mounted as to react between a plug 236 at the end of stem 226, andthe valve 221, thereby tending to hold saidvalve 221 upon its seat. Alsoat this end of the pressure control valve and mounted in the `pressurecontrol valve cylinder 223 there is a spring 234 which reacts betweenthe plug 236 and a plug 236a which closes the end of the cylinder 223.

In operation, oil under pressure from the conduit 222 enters thepressure control valve through conduit 231. By a system of levers, whichwill later be more fully described, the throttle control position isreflected by the movement of a lever 238, the end of which lever abutsagainst the projecting cylindrically shaped abutment member 229. Asshown in Fig. 3, small throttle openings are indicated when the end oflever 238 is near the maximum position to the right, and increasedthrottle openings are indicated by movement of the lever 238 to theleft, as viewed in Fig. 3. It is apparent, therefore, that for smallthrottle openings the valve stem 226 will be only slightly moved towardthe left from its maximum right hand position and will thereforecompress spring 234 a small amount and release spring 233 a smallamount. The result is that valve 221 offers greater resistance to theoil pressure from conduit 231 and releases less pressure than is thecase when the end of lever 238 is positioned a considerable distancetoward the left in Fig. 3, thereby compressing the spring 234 andreleasing spring 233 to a greater extent and causing valve 221 to offerless resistance to the oil from conduit 231 and therefore releasing alarger pressure.

The outlet valve 228 is held closed by spring 232 and when the pressureinside the pressure control valve exceeds that necessary to lift valve228 off its seat the pressure will be reduced by outlet of fluid to thesump through valve 228. The spring pressure holding valve 228 on itsseat is increased with larger throttle openings by the movement ofabutment 229 to the left. With increaselin throttle opening the movementof the valve members toward the left reduces the compression on inletvalve spring 233 and increases the compression on outlet valve spring232, thereby increasing the pressure of the fluid allowed to fle-wthrough the pressure control valve to the selector valve as the throttleopenings increase.

(d) Selector valve and connections to actuating units The function ofthe selector valve is to direct chronizing unit. A cylindrical openingfor movement of the valve is provided by a sleeve member 258 which ismounted in a substantially cylindrical drilled opening in the housing.This sleeve member provides a plurality of inlet and outlet openingsleading to and from the central cylindrical opening in which a selectorvalve cylinder 25| is mounted for sliding movement. The cylindricalvalve 25| has a central opening 252 extending longitudinally through itscenter and has provided on its surface suitable grooves and drilledopenings, the grooves being for the purpose of connecting certain inletand outlet passages brought in alignment therewith, and the drilledopenings being for the purpose of releasing pressure from such outletswhich it is not desired to hold under pressure, it being understood thatthe central opening 252 of the selector valve is connected with thesump.` There are two main pressure conduits leading to the sleeve member258 and connecting with the inlet openings thereof, i. e., conduit 253leading from the pressurecontrol valve and conduit 256, which is anextension of conduit 22| and brings the pressure directly from theaccumulator cylinder 201.

' It is to be remembered that the inlet openings in the selector valvesleeve 250 (Fig. 4) are drilled through the sides of the sleeve member250 substantially in a horizontal plane through the axis of said sleeve.As shown in Fig. 4 the conduit 253 leads to an annular groove 253aaround the sleeve member 250, which groove has connecting slots 254 cutlongitudinally of the sleeve, one of said slots being provided at eachside of the sleeve member. From the slots 254 there are drilled openings254a, 254b and 254e which are spaced as shown in Fig. 4 and extend intothe center of the selector valve.

A similar construction is employed to effect inlets into the selectorvalve from the conduit 256, as shown at the right hand end of the sleeve250 in Fig. 4, an annular groove 256a-being provided around the'selector valve sleeve 250, said annular groove connecting with grooves251 on each side of the sleeve member. From the grooves 251 drilledopenings 251a and `2511) spaced as shown'in Fig. 4 are provided. 'I'herehave now been described two sources of pressure coming to the selectorvalve, each with a separate system of spaced inlet openings any one ofwhich will supply fluid under pressure into the central bore of theselector valve cylinder if not closed by the surface of the selectorvalve.

A system of four outlet conduits, all of which take their pressure fromthe selector valve, is provided to direct the pressure to the twoclutches and to the synchronizer operating unit. These conduits areshown in Figs. 3 and 4 as conduits 258 and 259 for clutch actuation, andconduits 213 and 214 for actuating the synchronizer unit. Each of thesefour conduits receives its pressure from conduits leading from the topand bottom of the selector valve sleeve member 25|) by pairs of conduitsshown in Fig. 5 as 219 and 289, with connecting drilled openings 2190,and 28|la. By inspection of Fig. 3 it is noted that the conduits 258,259, 213, 214 are spaced along the selector valve cylinder, the clutchoperating conduits 258 and 259 being located toward the left end, asshown in Fig. 3, and the synchronizing conduits 213 and 214 beingadjacent the right hand end of the selector valve unit.

For the purpose of description of the selector valve unit it is herestated that conduit 258 carries pressure to actuate the clutch fordirect ries uid under pressure to the left hand end of the synchronizercylinder, shown in Fig. 4, for the purpose of moving the synchronizeroperating shaft 808 from left to right and the conduit 218 carries fluidunder pressure to the opposite or right hand end of the synchronizercylinder to move the synchronizer in the opposite direction.

.'Ihe connecting conduits which feed pressure to cylinder 82 (Fig. 1) toactuate the direct drive clutch 'I I from conduit 258 are 25| (Fig. 3),283 (Fig. 4), 288 (Figs. 1 and 4) and 281 (Fig. 1). I'he conduits whichconnect with 258. to feed pressure to cylinder 8| (Fig. 1) to actuatethe low and over-drive clutch I0 are 282 (Fig. 3), 288 (Fig. 4), 288(Figs. 1 and 4) and 21| (Fig. l). For operating the synchronizercylinder conduit 218 (Fig. 3) extends from conduit 214 and into theright hand end of the synchronizer cylinder through conduit 211 (Fig.4a). Similarly, conduit 218, for feeding pressure to the opposite end ofthe synchronizer piston, has connecting conduit 215 (Fig. 3) which leadsinto conduit 218 (Fig. 4a).

The selector valve is shown in Figs. 3 and 4 in `position to effect lowspeed drive of the transmission. A groove 28| extending around the outerperiphery of the selector valve 25| connects the inlet conduit 254b(Fig. 4) with the outlet conduit 258 (Fig. 3 thereby feeding pressure toclutch I0. It is noted that the drilled inlet opening 254D is arestricted opening and that therefore the fluid under pressure is fed insuch manner as to effect a slow engagement of the clutch I0. Referringto Fig..3 it is noted that a drilled opening 282 is provided in the topand bottom of the selector valve cylinder which aligns itself with theconduit 258 leading to the direct drive clutch and because of thisalignment of the drilled opening 282 with the conduit 258 any saidconduit 288, thereby producing a slow release of the low speed clutch.The same movement of thelselector valve places the groove 28| inalignment with the conduit 258 for actuating the direct drive clutch,the pressure coming to the groove 28| from the unrestricted opening 254e(Fig. 4). The result of this movement has been to release the low speedclutch I8 and to actuate the direct drive clutch II, a, reversal of thecondition previously existing'. Subsequent movement of the selectorvalve toward the left after the above reversal of the clutches has beeneected places a groove 285 in alignment withl conduit 218 (Fig. 3) thusfeeding pressure from the drilled opening 251D (Fig. 4) and placingdrilled opening 286 (Fig. 3) in alignment to release pressure fromconduit 218. The result of this movement of the selector valve is tofeed pressure to the right hand end of the synchronizer operatingcylinder 80| (Fig. 4) and release pressure from the left hand end of thecylinder, thereby producing movement of the synchronizer from right toleft, as viewed in Fig. 4. It is noted that this movement is takingplace during the time the direct drive clutch is in operation. Thispressure flow continues until the synchronizer has been moved to itsmaximum left position (Fig. l), thereby connecting the gear I1 with theshaft I4. No change in drive results with this movement since the clutchI8 is at this time disengaged. However, on further increase in car speedand further movement of the selector valve from right to left, as shownin Fig. 3, a longer annular groove 282 is brought into alignment withthe conduit 258 (Fig. 3), thereby again actuating the clutch I8 to whichthe conduit 258 feeds pressure. Referring to Fig. '4. the pressure comesinto the groove 288 when said groove bridges the two inlet drilledopenings 254a and 25411, thereby do eifecting anunrestricted flow offluid to actuate pressure which may exist therein is released into thecentral opening 252 of the selector valve which is connected with thesump through suitable drilled openings.

As the speed of the car increases the selector` valve is moved fromright to left, as shown in Figs. 3 and 4, by the movement of thedifferential lever 281, and during the time which the low speed clutchhas been engaged, as above described, a. groove 284 of the selectorvalve has been aligned to feed pressure to the conduit 218 (Fig. 3),receiving such fluid under pressure from inlet opening 251b (Fig. 4).Also a drilled opening 288 (Fig. 3) has been aligned with conduit 214 torelease pressure from said conduit and from the right hand end of thesynchronizer operating cylinder. The result of this connection of theconduits 213 and 214 has moved the synchronizer unit to connect thegears 24 and 25 with the shaft 'i4 (Fig. 1), such connection of gearingbeing the clutch instead of the restricted flow afforded by 254b aloneon the previous actuation of the clutch. It is understood that with thesynchronizer in the maximum position toward the left, as abovedescribed, the gear ratio effected is an over-drive, as previouslydiscussed with reference to the general gear arrangement.

(e) synchronizer, control cylinder and control parts l As previouslymentioned, the synchronizer is actuated for the purpose of changing thegear connection of one of the clutches while the other is engaged. Inits general construction the synchronizer unit is similar to units usedin other manually operated transmissions wherein the driver of the carchanges the gear connection while the clutch is thrown out. 'I'heessential parts of such a unit are shown in Fig. 1 at I8' and comprise asliding hub member which carries conical shaped surfaces which onsliding movement of the member will frictionally engage other conicalsurfaces on adjacent rotating parts, thus gradually bringing the Itworotating parts up to the same speed of rotation, and after this isaccomplished the shafts are permanently connected by movement of acollar which is provided in its inner circumference with toothedprojections which are designed to fit with projections on the hub and onthe adjacent rotating member thereby completing a positive connection.As shown in Fig. 1, the unit designed for use with the transmission hasseveral novel features. A hub 48| mounted free to slide on shaft I4 andsecured to rotate therewith has conical surfaces 402 and 403 providedadjacent its ends and hasy a sliding collar 404 which is normally heldfrom axial movement relative to the hub 40| by a plurality of springurged balls 405 which are pushed outwardly from the periphery of the hub40| into a groove 406 in the inner surface of the collar. When thesynchronizer 'collar is moved to the right or left, as shown in Fig. 1,by the action of the previously mentioned synchronizer fork, the conicalsurfaces 402 or 403 will contact adjacent surfaces on the gear membersI3 or the gear |1 and by this frictional contact will bring thesemembers up to the rotative speed of the synchronizer hub and shaft I4before the connection is finally completed by the movement of the collar404, which movement occurs when the force to shift the collar issufficient to break the holding force of the spring connection effectedby the balls 405. When this connection is broken the two rotatingmembers are connected positively together by the intermeshing of theinternal teeth on the inside of the collar 404 with teeth on the hub ofgear I1 or on the hub of gear I8.

A greatly improved means of effecting fric- 'tional contact of theconical surfaces is provided,

as shown in Fig. 1, by the use of a floating member 401 having two innerconical surfaces so that when the conical surface 402 of the hub 40|contacts one of these surfaces the member will slide along with the hubmember and contact another surface on an adjacent floating member 400.In this manner a plurality of surfaces is provided and results in agreater frictional torque, thereby bringing members and 40| to the samerotative speed in much less time than would "be possible with a singlefrictional surface, provided i the same pressure be applied in eachcase; or in the same time with less force. In case the same force beused to bring about synchronization in the same length of time, thisconstruction which employs a plurality of successively engaged conicalsurfaces allows the use of a relatively large contacting angle andprovides the same synchronizing power as with a single surface andsmaller angle. The larger contacting angle is of advantage because conesof greater angle have less tendency to stick together after the pressureis removed, thereby leaving the members i8 and 40| free to turn slightlywith respect to each other, after the holding force of the balls 405 hasbeen broken, to permit the teeth on collar 404 and member I8 to engage.

In order that the synchronizer be properly operated by an automaticunitit is necessary that the actuating member` be given a movement which isvarying in its rate of speed, the necessary variation being a fastmovement of the operating member during the approach or idle portion ofits travel followed by a pause during the portion of the travel in whichthe synchronizing cones are being held in contact, followed by a fastmovement for quickly effecting a positive connection by engagement ofthe projecting teeth or jaws on the inner surface of the collar with theadjacent gear unit.

For the purpose of effecting the above outlined result a fluid pressureoperated synchronizer cylinder see Fig. 4, is provided, the primaryparts being the fluid pressure operated piston 302 with slidably mountedshaft 303 and shifter fork 304. The shifter fork 304 is connected withthe synchronizer proper by the conventional circumferential recess 306.The connections of the fluid pressure system to this unit havepreviously been indicated up to the points 216 and 211 in Fig. 4a..position of the selector valve is such as to require a movement of thesynchronizer to the right to connect the lower gear ratio unit I3, theselector valve will allow fluid under pressure to enter through theopening 210 and pass out through the opening 211. A check valve is usedat both of these openings which essentially comprises a star-shapedplate with a small orifice in its center mounted in both of the openings216 and 211. When the flow of fluid under pressure is into the opening216, for instance, the star-shaped plate 301 is caused to move upwardlyoff the opening 213 and allow unrestricted ow therethrough and themovement of the piston forces `fluid out of the opening 211 and causesthe star-shaped plate 301 in that opening to rest against the fiatsurface and restrict the flow therethrough. The result accomplished isan unrestricted inflow at one end of the cylinder and a restrictedoutflow at the other. It is noted that there are two other outlet ports308 and 309 a distance from the ends of the synchronizer cylinder (seeFig. 4a). Considering the movement vof the piston to the right, the port309 during the first portion of the travel being uncovered by the pistonallows substantially unrestricted outward flow, and, therefore, fastmovement of the piston during the first part of the travel. However, asthe piston covers the port 309 the piston moves more slowly as the flowis then restricted by the aforementioned star-shaped plate 301e.

A pause in the motion of the synchronizer during cone contact is assuredby the manner of mounting thepiston 302 upon the shaftA 303. As shown inFig. v4 the end of the shaft 303 projects into the recessed innerportion ofthe piston 302 and is yieldably secured to said piston by twosprings 3| and'3l2, these springs being on opposite sides of an abutment3|3 on the shaft 302. Suitable details to assure the reaction of thesprings against this abutment are provided,

namely, two rings 3|4 and 3|5 and a locating ring 3|6 in the piston. TheSpring connection above described permits the shifter fork and synchronizer to stop when the cones make contact. The piston 302, however,continues to move slowly during this period, its rate of motion beingcontrolled by the star-shaped orifice 301 or 3|l1a. The movement ofpiston 302 against spring 3| I or 3|2 builds up a pressure which servesto press the conical surfaces of the synchronizer together forsatisfactory frictional engagement to perform the function of bringingthe new gear train to the same speed of rotation as member 40|. Thestrength of the springs 3|I and 3|2 and the size of the hole in thestar-shaped orifice 301 or 301a are such that this pause continues asuillcient time so that synchronization is completed before enoughpressure is built up on spring 3|| or 3|2 to cause the shifter fork andshaft to disconnect the collar of the synchronizer. A nal relativelyfaster movement of the synchronizer collar to effect nal connection ofthe unit will result from the ensuing release of spring 3|| or 3|2. Thislast movement may be better understood by reference to Fig. l, whereinthe sliding collar of the synchronizer is shown. Considering thesynchronizer moving to the left it is apparent that the cones arebrought into contact by movement of tre entire synchronizer. During thetime when the spring 3| is being compressed and until sufficientpressure is built up by the spring 3| the collar 404 and hub 40| of thesynchronizer unit In operation when, for example, the y l the piston isdrained back to the sump. In this way leakage of pressure pastthe pistonis prevented from building up a back pressure on the outlet side therebyassuring that full inlet pressure will always be available to move thesynchronizer piston. This construction was previously mentioned inconnection with the diagrammatic showing in Fig. 2.

(f) Synchronizer and selector valve interlock Still referring to Fig. 4,it is to be noted that there are two recesses 3I1 and 3I8 so positionedthat when, for example, the movement of the synchronizer shifter fork304 to the right is complete the recess 3|1 will come into alignmentwith a pin 3|9. This pin is mounted to have a beveled projecting endsuitable for contacting a. beveled ring 32| on the selector' valve 25|.During the time that the shifting has been taking place the end of thepin 3I9 has been in contact with the ring 32| and has prevented themovement of the selector valve, but on the completion of the shift thepin 3|9 `drops into the recess 3I1 on coming into alignment therewithand the selector valvev is released. In other words, the mechanism justalso contemplated that a governor might be used employing a plurality ofsprings of diil'erential eifectv designed to cause the valve mechanismto shift at suitable vehicle speeds, as disclosed in my co-pendingapplication, Serial No. 715,065. In the design here shown the collar 359has an annular recess 343 in which a suitable projection on a lever 304is adapted to fit in such manner that' when the collar 359 slides on theshaft I4 the lever 334 will be carried therewith (see Fig. 1). It is tobe noted that an increase inV speed of the shaft I4 causes the top endof the lever 334 to swing toward the left as shown in Fig. 1.

(h) Controls from governor and throttle to diderential lever Aspreviously mentioned, the selector valve which directs the flow of fluidunder pressure to the several mechanisms is controlled by the combinedaction of throttle control position and vehicle speed. A differentiallever 231 shown in Fig. 3 is pivotally mounted at its center on theprojecting end of the selector valve One end 208 of this lever 281 (thelower end as viewed .in Fig. 3) is actuated by the vehicle speedgovernor and the opposite end 289 is actuated by a member which moveswith the throttle control, as will now be described. Y

To transfer the governor movement to the end of the differential lever231 the mechanism shown in Figs. 1, 7 and 8 is provided. As shown inFig. 7, the end of the lever 364 is connected by a rod 335 to a lever361 projecting downwardly from va. shaft 388 (see Figs. 1 and 8) whichextends transversely across the top of the transmission.

described assures that the selector valve cannot move to apply clutch I0until the synchronizer shift is completed,` and collar 404 is inposition to transmit the power applied through clutch I0. The action issimilar when the synchronizer completes its movement to the left, pin320 being brought into alignment with recess 3|0 thereby releasing theselector valve for movement toward the left with increase in speed.

(y) Governor operated by vehicle speed Referring to Fig. 1, there isshown a governor mounted on the end of the shaft I4 at the rear of thetransmission housing. 'I'he housing 350 for this governor unit is shownas bolted to the end of the main transmission housing and this housingalso includes a bearing 35| and a Speedometer drive gear 352 so mountedas to make possible the assembly. or a conventional fitting 353 forlconnection to the propeller shaft of the vehicle. 'I'he governor itselfis made up of a member 354 which issecured to rotate with the shaft |41A plurality of bosses 355 project radially out from the fitting 354 andhave pinned thereto counterweight arms 351. Similarly shapedcounterweight arms 358 are secured to a sliding collar 359 mounted toslide upon the shaft I4. Weights'30l are mounted on the pins whichconnect the two counterwight arms 351 arid 355 so that when the shaft I4rotates carrying with it the member 354, .the counterweights and armsand the collar 359, the speed of rotation causes the weights 36| tfo bethrown outward by centrifugal force. A spring 362 is mounted between themember 354 and the collar 359 and the centrifugal action of the weights36| is therefore resisted by the spring 362 and therefore the locationof the collar 359 on the shaft I4 is indicative of the speed of rotationof the shaft I4. It is Itswill be apparent from inspection of Figs. 1, 7and 8 and on consideration of the direction of the movement of thegovernorthat clockwise rotation of shaft 360 as viewed in Fig. 1 wouldindicate increase in vehicle speed as reflected by the main shaft I4 ofthe transmission. Also referring to Fig. 6 wherein the shaft 300 isshown with a depending lever 369 secured thereto, it is noted that theend of the lever 369 is secured to the end of the differential lever281, thereby completing the connection from the governor to the end ofthe diil'erential lever, as shown at 203inFigs.3and 6.

By appropriate linkages the engine throttle control is connected torotate the shaft 31| shown in Fig. 3 in such a manner that clockwiserotation of the shaft 31| as viewed in Fig. 3 is indicative of increasein throttle opening. The shaft 31| is also shown in Fig. 6 and issecured to a lever 238 which is connected to the top end of thedifferential lever 201 by link 312. The lower extension of lever 230also acts to apply the pressurecontrol valve by contact with theprojecting end 229. By the connection effected by the upper portion oflever 233 the throttle control is connected to the opposite end 289 ofthe differential lever 281 from that used to connect the governorcontrol and makes possible the positioning of the selector valve by thecombined action of throttle control position and vehicle speed. A spring313 is mounted to hold the top end of the differential lever 281normally toward the left (Fig. 3) and the opening action of the throttlerod is to move the lever in the opposite direction. yThere is alsoprovided a spring 314 which serves to control the movement of theselector valve by contact with suitable projections on the projectingsurface of the valve, thereby to define the steps in the movementthereof, as shown in the diagrammatic view Fig. 2.

asias-1s In Figs. 3 and 6 there is shown a member t88a which is L shapedand is pivoted on the end of the shaft 31| and free to tilt about thispivot. The end of the member sets against the end of the pressurecontrol valve 229, as shown in Fig. 3, and the projecting portion is soshaped that when the governor control at 288 is so positioned as toindicate a relatively high vehicle speed the end of the member 288 willhold the member 288a against the end of the pressure control valve andprevent it from entirely releasing the pressure, which would resultwhenever the throttle was released, regardless of the speed, if thisstop were not provided. The throttle lever 238 has a projecting endwhich also controls the movement of the pressure control valve so thatwhen the governor control member 288 is in a relativelyv low speedposition, as shown in Fig. 3, small throttle openings will allow thepressure control valve to extend a maximum distance to the right, whichcondition will release all pressure and throw out any clutchwhich may beengaged, thereby producing a neutral (or free wheeling) condition, andpermit the car to be stopped without stalling the engine. The abovedescribed mechanism allows such a condition to occur only at relativelylow car speeds and released throttle, whereas at high car speeds thefree wheeling of the car is prevented by the action of the member 288awhich is held against the end of the pressure control valve.

(i) Reverse interlock In order that it will not be possible for theautomatic control of the transmission to throw the gearing into highgear when the manual shifting mechanism has been used to place the gearsin position for a reverse drive, the mechanism shown in Figs. `8 and 9has been provided. The shifter fork 28 shown in Fig. 8 is for thepurpose of moving the reverse idler along the shaft 2l and as shown inFig. 9 a two armed lever 458 is mounted with one of its arms 45|positioned to ride upon the top of the shifter fork arm 28 when saidfork is in such longitudinal position as to eect reverse drive.l Such apositioning of the lever as is show n in Fig. 9, produced when it isriding on top of the fork 28, positions the end 452 of the leverupwardly toward a projecting arm 453 secured to be rotated with theshaft 368 which it will be remembered is actuated by the vehicle speedgovernor and is connected through several leverages to actuate theselector valve. The result of the aforementioned positioning of the end452 of the lever 458 is to place it in position to act as a stop so thatthe shaft 368, and therefore the selector valve, cannot be actuated toeiect high gear. When the shifter fork is actuated to place the reverseidler out of operation by longitudinal movement of the fork 28 it isapparent that the lever 458 will drop by gravity out of the way and bepositioned against a stop pin 454 snown in Fig. 9 and in such positionwill allow the shaft 368 and its connected parts to operate withoutinterference.

, quirement that the use of an exceptionally heavy and cumbersomerotating weight suspended at the end of the flywheel housing be avoided.A 7

heavy overhung weight, if no support were provided on the outer end,would be very objectionable as it would throw heavy loads on the end ofthe crankshaft and on the flywheel and clutch housing. There is anotherimportant problem in this connection in that it is very essential thatnone of the fluid which is used to actuate the fluid pressure mechanismcan be allowed to be thrown from the rotating unit toward the clutches.Both of these problems have been considered and solved by the novelconstruction which is shown in Fig. 1. The entire overhanging portion ofthe fluid pressure actuating unit is supported in the large bearing 588provided in the collector ring casing 468 which is secured to thetransmission housing and serves both as a means to carry the collectorring conduits 266 and 269 as well as to provide a bearing for therotating unit. It has been previously mentioned that all of the pistonsfor actuating the clutches rotate with the flywheel and such aconstruction is shown in Fig. 1. The piston housing 38 projects into theiiywheel portion' of the transmission housing and rotates with theflywheel but the entire unit is provided with a cup-shaped cover 46Iwith a ange edge 462 which extends back into the next compartmentrearward of the flywheel casing. When the unit rotates this cup-shapedmember collects such oil as may leak past the pistons, the `centrifugalforce causing this oil to flow back on the cup-shaped member to theflange 462 from which it is thrown on the adjacent Wall of thestationary casing to flow into a sump groove 463, which groove is`provided with a drain to allow the oil to flow back into the oil sump.This construction makes possible the use of the dry plate clutchactuated by a iiuid pressure unit which rotates with the clutches butdoes not have the very objectionable feature of fluid conduits adjacentto it with the possibility of leakage into the clutches. As previouslynoted, the housing 38 is secured by set screws 38a to flywheel i2 andtherefore endwise reaction from the pistons is transmitted to theilywheel and is not imposed on the bearings in the transmission orengine. The housing 38 is mounted with a limited lateral freedom ofmovement so that axial misalignment between the rotating ywheel clutchhousing and the transmission unit will not `seriously interfere with thecooperative operation of the housing 38 and the parts with which itrotates. This freedom of movement is made possible by a loose mountingof the collector ring casing 468 in the transmission case at 465 andalso by a loose mounting of the projecting end of the housing 38 at 466where it connects with the rotating ye wheel I2. The right hand end ofthe housing 38 rotates in the collector ring casing 468 so that the saidcollector ring casing 468 and the housing 38 form a unit which, togetherwith the sleeve I5, has a limited freedom of tilting movement because ofthe loose mounting, the end of the sleeve I5 being secured to the clutchplate and free to move on release of the clutch. By the above describedmounting it has been found that such misalignment between the flywheelandthe adjacent parts is adequately compensated so that a satisfactorymounting of the several rotating parts is accomplished withoutobjectionable binding due to misalignment.

(1c) Details of clutch construction to adapt for automatic operation Itis very advantageous in connection with a clutch which is to be actuatedby uid pressure mechanism that there be some kind of a cushionlng meansprovided giving a delayed action so that when the fluid pressure isapplied by whatever means is used to push the plates of the clutchtogether there will be a time interval after which the clutch will makepositive engagement. It has been found after a considerable period ofexperimental work that the use of a clutch facing with a resilientmounting such as shown in Figs. 11 and 12 produces very desirableresults. As shown in the two figures, one clutch facing 41|) is securedt the clutch plate by rivets without resilient mounting, while thefacing on the opposite side of the plate 412 has a plurality of springclips 413 bent into the shape as-shown and riveted at the center to theclutch facing and at one end to the plate. The result of such aconstruction is to resiliently mount the clutch facing relative to theplate so that when the clutch is engaged in the usual manner it willtake up slowly because of the use of the resilient mounting.

Although I have described my invention as applied to a specific type ofunit found practical in actual operation, I do not desire to limitmyself to the exact details of the construction shown and describedherein but rather to the scope of the following claims.

I claim:

1. In a transmission system for automobiles including a mechanismproviding a plurality of driving connections of different Aspeedmechanical advantage ratios, a clutch for transmitting power through oneof said driving connections, a second clutch for transmitting powerthrough another of said driving connections. and means for releasing oneclutch and applying another to effect a change in ratio, including meansto produce a different rate of release and application of said clutcheswhen changing from a lower to a higher speed ratio than when changingfrom a higher to a lower speed ratio.

2. In a transmission' having a plurality of clutches for effectingdriving connections of high and low speed mechanical advantage ratiosactuated by fluid under pressure characterized by a plurality ofconduits, a selector valve for selectively directing fluid underpressure to and from said conduits to effect high and low speed ratiosthrough said clutches, certain of said conduits leading to one of saidclutches having restricted passages of different area for feedingpressure thereto, and means for automatically rendering a passage oflesser area effective during a shift from a higher to a lower speedratio than when shifting from a lower t0 a higher ratio whereby saidclutches are applied more slowly when shifting into lower ratios. i

3. In a transmission for automobiles of the type wherein gear ratiochanges are accomplished by releasing one clutch and applying another,characterized by fluid pressure means for regulatlng the actuation ofthe clutches, and automatic means for altering the rate of actuation byrendering a passage of lesser area effective during a shift from ahigher to a lower speed ratio than when shifting from a lower to ahigher speed ratio.

4. In a fluid pressure operated automatic transmission, a selector valvefor directing fluid pressure to actuate said transmission for variousgear ratios, automatic means for positioning s'aid selector valve andmanually operated mechanism for positioning said valve when desired,means combined with said manually operated mechanism for providing aslower operation of said fluid pressure mechanism when said manuallyoperated mechanism is operated, said means comprising a branched conduithaving an unrestricted opening in one of said branches and a restrictedopening ln the other of said branches, a valve member operable with saidmanually actuated mechanism for closing said unrestricted branch therebyforcing said fluid under pressure to flow through said branch having arestricted opening therein.

5. In a transmission for automobiles of the type wherein gear ratiochanges are accomplished by releasing one clutch and applying another,characterized by means for regulating the actuation of the clutches, andautomatic means for altering the rate of actuation in such manner as toallow more time between the clutch release and engagement whenincreasing the gear ratio than when decreasing it. k

6. Ina power transmission system for automov biles, an engine, a fluidpressure operated clutch, a

plurality of gear trains, gear train shifting means for variouslyconnecting said gear trains to provide a variation in gear ratio, avalve for directing fluid pressure for applying and releasing saidclutch to connect said gear trains for operation by said engine, andpositive interlocking means for preventing the valve from applying theclutch before said gear train shifting means has completed itsconnection.

7. In a fluid pressure operated transmission having a plurality ofclutches controlling independent driving connections, mechanism forvarying the mechanical advantage ratio of one or more of said drivingconnections, a source of nuid pressure, a selector valve for directingfluid under pressure to successively operate said clutches, and positiveinterlocking means for preventing movement of said selector valve beforesaid mechanism for varying the ratio has completed a shifting movement.

8. In a fluid pressure operated transmission having a clutch foreffecting a drive through a gear train providing a plurality of gearratios, means for changing the gear ratio transmitted through said geartrain, and positive interlocking means for preventing the application ofsaid clutch until the gear ratio changing means has completed itsoperation.

9. A fluid pressure operated transmission for an automobile, comprisinga plurality of fluid pressure operated clutches, an engine, drivingconnections of different gear ratios controlled by said clutches, meansfor automatically actuating said clutches to make said different gearratios effective including means for operating said clutches in suchtimed relationship that there will be overlapped engagement between twoclutches when a gear change of said transmission is being effected froma lower to a higher ratio to prevent racing of said engine, and meansfor insuringcomplete disengagement of all of said clutches-when saidtransmission is automatically operated to effect a gear change from ahigher to a lower ratio.

10. In a variable speed power transmission system having a drivingmember and a driven member and a plurality of means for providingdifferent speed ratios between said members comprising,a clutchconnecting the driving and driven members through either of two speedratios, a second clutch connecting the driving and driven membersthrough another speed ratio, a third clutch for selecting one of thesaid speed ratios connected through said first mentioned clutch, andpositive interlocking means interposed between said nrst mentionedclutch and said third clutch to prevent engagement of said first clutchuntil engagement of said third clutch is completed.

11. In a variable speed power transmission system, a driving member anda driven member, a plurality of driving connections, a plurality ofprimary clutches for selectively connecting said driving connections toeffect a drive between said driving and driven members, secondary clutchmeans associated with one of said driving connections for varying theratio thereof, a control member for actuating said primary and secondaryclutches, and an interlocking member between said secondary Clutch andthe primary clutch connected therewith to hold said primary clutch fromengagement when said secondary clutch is disconnected.

12. In a `iluid pressure mechanism for automatic operation of atransmission comprising a plurality of primary clutches operable toselectively connect a plurality of driving connections of different gearratios for operation, secondary clutch means for varying the gear ratioof one of said driving connections, an interlock between the saidsecondary clutch and the primary clutch connected therewith positionedto prevent ensagement of said primary clutch when said secondary clutchis disconnected, fluid pressure operated units for actuating each ofsaid primary and secondary clutches, and a selector valve for directingfluid under pressure to said units thereby to actuate said primary andsecondary clutches in timed relation with each other.

13. In a transmission, a main driving shaft extending therethrough forconnecting with the driving wheels of a vehicle, a flywheel rotatingwith the power plant of said vehicle, a clutch operable to connect saidywheel `with said driving shaft, a sleeve surrounding said driving shaftand rotatable to drive a gear train providingia gear ratio between saidsleeve and said driving shaft, a clutch operable to connect saidflywheel with said sleeve, a second gear train, independent clutch meansfor connecting said second gear train in combination with said firstmentioned gear train to vary the ratio between said sleeve and saiddriving shaft, an interlock between said independent clutch means andsaid second mentioned clutch positioned to prevent engagement of saidsecond mentioned clutch when said independent clutch means isdisconnected, and control mechanism for operating said three clutches intimed relation whereby said transmission is operable to provide astarting speed by operation of said second mentioned clutch, a directdrive by operation of said first mentioned clutch, and a third speed bya second actuation of said second mentioned clutch following actuationof said independent clutch means.

14. In a transmission for automotive vehicles, a gear train operable toprovide a gear ratio satisfactory for starting said vehicle, a clutchfor connecting said gear train to the power plant of said vehicle, adriving shaft connecting said transmission with the wheels of saidvehicle, a clutch operable to connect said power plant directly withsaid shaft, independent clutch means for varying the ratio of said geartrain, an interlock between said independent clutch means and said rstmentioned clutch positioned to prevent engagement of said firstmentioned clutch when said independent clutch means is disconnected,whereby on operation of said first mentioned clutch said gear train canbe used for starting said vehicle and said second mentioned clutchoperated to effect direct drive on release of said first mentionedclutch and subsequently said 'independent clutch operated to change theratio of said gear train while said direct drive clutch is in operationwhereby a gear train of modified ratio is available when said firstmentioned clutch is again actuated and said second mentioned clutch isreleased.

i5. In a transmission, a main driving shaft, a counter-shaft, a sleevemounted for rotation around said main driving shaft, a rotating memberoi' the power plant positioned in the forward end of said transmission,a pair of independent gears rotatable on said driving shaft andsynchronizer clutch means for connecting either of said gears to saiddriving shaft, a gear train connecting said sleeve with one of said pair-of gears and a. second gear train connecting said sleeve with the otherof said pair of gears, a clutch operabie to connect said driving shaftdirectly with said rotating power plant member, a second clutch operableto connect said sleeve with said power plant member, an interlockbetween said synchronizer clutch means and said second clutch positionedto prevent engagement of said second clutch -when said synchronizerclutch is disconnected, to provide direct drive or two speeds ofdifferent gear ratio.

16. In a fluid pressure mechanism for automatically operating atransmission having a plurality of gear ratio units, a selector valvefor successively directing fluid under prese sure to actuate said unitscomprising a plurality of conduits, one for each of the said gear ratioumts, said selector valve having some of said conduits of morerestricted area opening than others in such a relation that when saidopenings are placed in position on operation of said valve to directfluid to actuate said gear ratio units a different rate of connectionand release of said units will result when changing from a lower to ahigher ratio than when changing from a higher to a lower ratio.

17. In a power transmission system for automobiles, a plurality of geartrains providing various gear ratios, friction clutch means for makingeach gear ratioeiective, means for successively operating said clutchmeans including means for separately regulating the rate of actuationand release of said friction clutch means for one of said gear ratiosindependently of the others comprising a selector valve for successivelydirecting fluid under pressure to actuate said friction clutch meanshaving a plurality of conduits, one for each of said friction clutchmeans, said selector valve having some of said conduits of morerestricted area opening than others in such a relation that when saidopenings are placed in position on operation of said valve to directfluid to actuate said friction clutch means a different rate ofconnection and release of said friction clutch means will result whenchanging from a llgjver to a higher ratio than when changing from a gherto a lower ratio.

18. In a uid pressure operated automatic transmission, a selector valvefor directing fluid under pressure to actuate said transmission forvarious gear ratios, means combined with said selector valve forproviding slower operation of said fluid pressure mechanism, said meanscomprising a branched conduit having an unrestricted opening in one ofsaid branches and a restricted opening in the other of said branches, avalve member operable for closing said unrestricted branch therebyforcing said fluid under pressure

